French patent document FR-A-2 598 209 describes a device for remotely lining the end of a steam generator tube in a pressurized water nuclear reactor, which tube is fitted into a thick tube plate by tube expansion, with a water box being located beneath the tube plate and being accessible from the outside by means of an inspection hatch. The method used comprises inserting a sleeve into the end of the tube, expanding the sleeve diametrically in two zones in the vicinity of said end, one of said zones being inside the thickness of the tube plate and the other beyond said tube plate, then expanding the sleeve by rolling in each of the expansion zones in order to lock it into place, said device including a handling member provided with an arm whose end can be placed beneath the tube plate and in vertical alignment with any one of the tubes, and a tubular guide element fixed to the end of the arm in a direction perpendicular to the tube plate, a flexible tube having one of its ends near the tube plate fixed to the tubular guide element and passing through the manhole so that its opposite end lies outside the water box, a loading and handling assembly connected to the end of the flexible tube which is outside the water box for the purpose of displacing a sleeve inside the flexible tube with a hydraulic expander being located inside the sleeve and fixed for displacement purposes to the end of a flexible tubular cable fed with a hydraulic fluid under pressure, and a handling and expansion assembly including tooling for expanding a tube by rolling fixed to the end of a flexible tubular element associated with a handling member disposed outside the water box for the purpose of displacing it inside the flexible tube, and connected to drive members by means of a flexible element passing through the flexible tubular element.
However, such a device cannot displace any type of tool and nor can it verify that the various operations, in particular the operation of expansion by rolling, are performed properly. When a sleeve is to be expanded by rolling inside the tube beyond the tube plate under control of the drive members of the handling member from outside the water box and by means of the flexible element passing through the flexible tubular element, there is no way of checking that the motion imparted by the drive members is properly transmitted to the expansion tool, nor is there any way of verifying that the expansion tool rotates through the required number of turns to ensure that the sleeve is fixed inside the tube in sealed manner. Nor is it possible to monitor the couple exerted by the tube expanding motor disposed inside the water box for the purpose of expanding tubes inside the tube plate by rolling. Finally, displacements of the flexible tube vary its elongation such that the positions of the tools at the end of the flexible tubular cable are not known accurately.
The object of the present invention is to ensure that the various operations of cleaning the insides of the tubes, of installing and docking sleeves in the tubes, of welding the sleeves in the zone in which they have been docked, of monitoring the welds, of expanding portions of the tubes by rolling and of heat treating the welded and expanded zones are performed with great accuracy and preferably while constantly monitoring the progress of said operations, thereby obtaining good sealing at the ends of the tubes fitted with internal linings.